睫状神经营养因子对视网膜保护作用的研究进展

睫状神经营养因了（CNTF）可诱导视网膜神经细胞分化，减少神经细胞凋亡和促进细胞再生。CNTF能促进轴突切断和视网膜缺血后RGCs的存活和轴突生长，减少视网膜色素变性动物模型的光感受器存活，为治疗视网膜缺血性损伤、神经退行性病变等视网膜疾病提供了可能。本就CNTF及其受体的分子结构、组织分布、基因结构及其表达调控和CNTF对视网膜作用的研究进展作一综述。     

视神经损伤时视网膜睫状神经营养因子受体的表达

目的研究睫状神经营养因子受体于视神经损伤后不同时间在视网膜中的表达情况,探讨外源性的睫状神经营养因子在神经损伤疾病中的应用价值。方法采用钳夹视神经的方法建立神经损伤的模型,在损伤后1、7、14、28d获取视网膜,提取总RNA及总蛋白,用半定量逆转录聚合酶链反应(RT-PCR)测定视网膜中睫状神经营养因子受体(CNTFR)αmRNA的表达,用WesternBlot方法了解损伤后不同时间CNTFRα蛋白水平的表达。结果在正常大鼠视网膜内CNTFRαmRNA无表达,在损伤后的1、7、14、28d均有一定水平的CNTFRαmRNA的表达,与正常对照比较差别具有显著性意义(P<0.01);损伤后备时间均有CNTFRα蛋白的表达,但CNTFRα蛋白的表达较弱。结论神经损伤后CNTF的表达先短暂升高以后持续下调,而CNTFRα-mRNA在损伤后4周内均有一定量的表达,提示补充外源性CNTF可能改善神经再生的微环境而发挥保护效应。     

急性高眼压大鼠视网膜睫状神经营养因子的表达

目的 :探讨大鼠急性高眼压前后睫状神经营养因子 (CNTF)mRNA在视网膜组织中的表达变化及意义。方法 :利用前房高眼压灌注法 ,使大鼠右眼维持在 110mmHg高眼压 30min ,然后恢复视网膜血供 ,并分别于灌注后 1d、3d处死大鼠 ,用半定量RT PCR方法检测大鼠视网膜组织中CNTFmRNA的表达情况。结果 :在正常大鼠视网膜组织中 ,CNTFmRNA有微量表达 ,急性高眼压后 ,其表达明显增高 ,第 1天、第 3天分别比对照组增加 37.0 9%和 2 2 7.4 2 %。结论 :大鼠急性高眼压损伤后 ,可通过内源性CNTF表达增加来应答视网膜神经节细胞 (RGCs)及其他细胞的损伤 ,保护视网膜及视神经 ,为外源性营养因子的应用提供理论依据。     

腺病毒构建过表达睫状神经营养因子对骨髓间充质干细胞的影响

目的：构建过表达睫状神经营养因子(CNTF)的腺病毒,利用腺病毒载体转染骨髓间充质干细胞,使其在体外持续高效表达CNTF,为视网膜病变的体外研究提供新途径。

方法：构建空载GFP-腺病毒及CNTF-腺病毒,取第3代BMSCs用于转染实验,分为3组：空白对照组(未转染腺病毒组)、阴性对照组(GFP-腺病毒转染组)和实验组(CNTF-腺病毒转染组)。ELISA测转染后1、2、3d各组上清液的CNTF蛋白分泌量。

结果：成功构建空载GFP-腺病毒及CNTF-腺病毒, 实验组的CNTF表达量明显高于空白对照组和阴性对照组,差异具有统计学意义(P<0.05)。

结论：利用腺病毒载体可使BMSCs在体外持续高效表达CNTF。     

退行性视网膜病变中睫状神经营养因子神经保护作用的研究进展

多项体内外及临床试验结果均证实睫状神经营养因子(CNTF)对光感受器细胞具有良好的神经保护作用,同时也对视网膜多种神经细胞的结构和功能产生不同的影响.CNTF对光感受器细胞保护作用的分子机制涉及Stat、Erk及Akt等信号传导途径,其中Müller细胞发挥着重要作用.细胞包囊技术为CNTF提供了有效的给药途径,在多种退行性视网膜病变的动物模型中均取得良好疗效,其临床应用中的安全性和有效性正在进行评估,这将为CNTF进入临床应用奠定基础.(中华眼科杂志,2011,47:568-572)

Abstract：

Ciliary neurotrophic factor (CNTF) has been showing neuroprotective effects on photoreceptors in a variety of in vivo and in vitro experiments and clinical trials. CNTF causes morphological and functional alterations in various retinal nerve cells. The neuroprotection mechanism of CNTF involves STAT-dependant, ERK-dependant, and Akt-dependant signaling technology (ECT) device is an efficient administration approach to deliver CNTF into the eyes, which is effective in retarding photoreceptor degeneration in several animal models with retinal degenerative diseases. The safety and efficiency of the device in clinical trials are also being evaluated currently for further clinical use in human eyes as a potential treatment.     

睫状神经营养因子对培养大鼠视网膜神经节细胞的影响

目的 观察不同浓度睫状神经营养因子(ciliary neurotrophic factor，CNTF)对培养大鼠视网膜神经节细胞（retinal ganglion cell，RGC）生长、存活的影响。 方法 取15只生后2～3d Wistar大鼠视网膜组织进行细胞培养，通过Thy-1单克隆抗体免疫细胞化学对培养的RGC进行鉴定。实验分对照组和10、20、40 ng/mlCNTF组（Ⅰ、Ⅱ、Ⅲ组），记录RGC存活时间，将培养第3、5、7天的RGC行四甲基偶氮唑盐（methylthio tetrazole,MTT）法测量吸光度(A)值［旧称光密度(OD)］。 结果 Thy-1单克隆抗体免疫组织化学检查显示培养3d的存活细胞90%以上为RGC。细胞存活期间实验组与对照组细胞均无明显突起,细胞体积无明显增大，实验组细胞存活时间比对照组长3~4d。培养第5、7d，Ⅰ组A值分别为0.075 8±0.0139、0.0693±0.0113，Ⅱ组A值分别为0.0902±0.0114、0.0825±0.0125，Ⅲ组A值分别为0.0792±0.0133、0.0653±0.0086，对照组A值分别为0.0620±0.0071、0.0513±0.0068。实验组与同时间对照组A值相比差异有显著性的意义（Ⅱ组与对照组相比P＜0.01，Ⅰ、Ⅲ组与对照组相比P＜0.05）。 结论 一定浓度的CNTF能促进培养大鼠RGC的存活，对RGC形态无影响。 (中华眼底病杂志, 2002, 18: 283-285)     

高水平稳定表达人睫状神经营养因子细胞株的建立

目的 建立能稳定且高水平表达人睫状神经营养因子（CNTF）的永久细胞株。方法 采有阳离子脂质体介导CNTF表达质粒转染C2C12、NIH3T3、、CRL-2302细胞，经氨甲喋呤筛选出抗性克隆后，分别采用原位杂交检测细胞中CNTF mRNA的表达，采用免疫组织化学染色、Western blot方法检测细胞浆中CNTF蛋白质的表达，采用ELISA法检测培养液中CNTF的分泌水平。结果 不同的克隆产生和分泌CNTF的能力不同，但其中产生和分泌CNTF能力最强的克隆其培养液中CNTF的质量浓度分别是C2C12-CNTF 11400pg/ml、NIH3T3-CNTF9069.071pg/ml、HLF-CNTF91046.15pg/ml及CRL-2302-CNTF77578.4pg/ml。结论 构建的多株细胞株均能持续、稳定、高水平表达和分泌CNTF。     

表达睫状神经营养因子的人胚肺成纤维细胞视网膜下间隙移植延缓RCS大鼠光感受器变性

目的以遗传性视网膜变性RCS大鼠为模型,探讨视网膜下间隙移植表达睫状神经营养因子(CNTF)的人胚肺(HFL)成纤维细胞治疗视网膜变性的可行性。方法通过脂质体将编码CNTF的表达质粒转入HFL成纤维细胞、MTX及ELISA筛选高水平表达CNTF的细胞克隆。手术显微镜直视下经角膜缘后1mm注射5μl含1×105个高水平表达CNTF的HFL成纤维细胞至4～5周龄RCS大鼠右眼视网膜下间隙,左眼不手术或注射PBS作为对照。分别于移植术后2、4、6、8、10、12及15周随机取1只鼠摘除眼球作光镜观察,随机取2只鼠摘除眼球作电镜观察。结果稳定转染CNTF的HFL成纤维细胞能高水平表达CNTF(91046.15pg/ml),7只经光镜观察的移植眼中的4只,其视网膜外颗粒层明显较对照眼厚,保存的光感受器数量明显较对照眼多(P≤0.002)。14只经电镜观察的移植眼中的10只,视网膜外颗粒层光感受器凋亡明显较对照眼少。在光感受器与视网膜色素上皮间堆积的盘膜碎片亦较少。宿主视网膜色素上皮细胞的形态保存较好,并可见吞噬小体。结论经过CNTF基因修饰的HFL成纤维细胞视网膜下间隙移植能够延缓RCS大鼠视网膜光感受器变性     

睫状神经营养因子对糖尿病早期大鼠视网膜神经组织的保护作用

目的：研究睫状神经营养因子（ciliary neurontrophic factor,CNTF）对糖尿病早期大鼠视网膜神经组织的保护作用。方法：选择40只健康成年雄性SD大鼠（250g-280g）一次性腹腔注射链脲佐菌素（Streptozotin,STZ）60mg/kg诱发糖尿病模型（DM）,将DM大鼠随机分组为DM＋CNTF组和DM＋BSS组。DM＋CNTF组给予玻璃体腔内注射CNTF（1.0μg/2μL）,DM＋BSS组注射BSS液（2μL）。分别观测0、4、8、12wk两组大鼠体质量和血糖变化,于4wk和12wk进行原位细胞调亡（TUNEL法）的检测及视网膜神经组织超微结构的观察。结果：DM＋CNTF组大鼠的血糖和体质量与DM＋BSS组比较无显著性差异（P〉0.05）。12wk时TUNEL检测DM＋CNTF组大鼠神经节细胞凋亡与DM＋BSS组相比减少（P〈0.05）。透射电镜下观察发现从4wk起两组大鼠视网膜神经组织出现细胞凋亡的改变,经CNTF治疗细胞凋亡改变有所减轻,表现为外节膜盘间隙减小,感光细胞水肿减轻及核染色质浓集减轻等。结论：CNTF对DM＋CNTF组和DM＋BSS组大鼠的体重及血糖无明显影响。CNTF治疗组结果显示对本实验糖尿病大鼠视网膜神经节细胞及感光细胞有一定保护作用。     

睫状神经营养因子对纯化培养大鼠视网膜神经节细胞突起再生的影响

目的观察睫状神经营养因子（ciliary neurotrophic factor，CNTF）对纯化培养大鼠视网膜神经节细胞（retinal ganglion cells，RGCs）突起再生的影响。方法取新生SD大鼠视网膜，消化并利用筛网纯化后接种于96孔板，加入不同浓度（10μg·L-1、20μg·L-1、30μg·L-1、40μg·L-1）CNTF作为实验组，不加CNTF作为对照。根据细胞形态及免疫细胞化学的方法鉴定细胞，观察RGCs生长规律，观测随机选取视野下的RGCs数和有突起细胞数（400倍荧光显微镜和相差显微镜）。结果 纯化的RGCs在含体积分数20％胎牛血清DMEM培养液中可存活30d。加入CNTF后3~5d，40μg·L-1组突起率显著高于对照组（P〈0.05）。7~15d，20μg·L-1、30μg·L-1、40μg·L-1组突起率显著高于时照组（P〈0.05），30μg·L-1、40μg·L-1组突起率显著高于10μg·L-1、20μg·L-1组（P〈0.05）。结论CNTF能显著促进RGCs突起再生，CNTF的浓度和突起率存在量效关系，一定浓度范围内．高浓度CNTF可较早促进突起再生。     

荧光金逆行标记检测CNTF基因眼内转移对视神经损伤大鼠的影响

目的通过荧光金逆行标记的方法,检测腺病毒(adenovirus,Ad)介导的睫状神经营养因子(ciliary neurotrophic factor,CNTF)对视神经钳夹伤大鼠视网膜神经节细胞(retinal ganglion cell,RGC)数目的影响。方法采用钳夹视神经法制作大鼠视神经损伤模型,夹伤后向大鼠伤眼内注射Ad-CNTF,在取材前7d进行荧光金逆行标记RGC,于伤后28d,对大鼠的视网膜铺片进行荧光金标记的RGC记数。结果伤后28d,单纯损伤组、PBS组、Ad-LacZ组视网膜标记RGC数均较低;CNTF处理组视网膜标记RGC数为每视野(12.11±2.29)个(n=9),高于前3组,且差异非常显著(P<0.01)。Ad-CNTF组视网膜标记RGC数为每视野(20.93±2.67)个(n=8),在各组标记RGC数中最多,也好于CNTF组,2组间差异非常显著(P<0.01)。结论视神经损伤后眼内单次注射Ad-CNTF,可明显增加钳夹伤后28d大鼠视网膜的标记RGC数。与单次注射CNTF相比,对损伤的RGC具有更加显著的神经保护作用。     

内源性睫状神经营养因子对青光眼鼠视网膜的保护作用

目的 探讨睫状神经营养因子(CNTF)蛋白在慢性高眼压性青光眼大鼠视网膜中的定位及表达情况.方法采用水下电凝巩膜静脉建立大鼠慢性高眼压性青光眼模型,在1、3、7、14、28 d分别摘取眼球,运用免疫组织化学和Western blot法检测大鼠视网膜CNTF蛋白的定位及表达变化.结果对照组大鼠视网膜神经节细胞(RGCs)层有少量CNTF蛋白表达,青光眼大鼠视网膜CNTF蛋白的表达显著增加,建立模型后第7～14 d表达量达到高峰,此时除了神经节细胞层外,内外核层亦发现有CNTF蛋白的表达,之后表达减少.结论青光眼大鼠视网膜内源性CNTF表达增加,可能与促进损伤的RGCs的存活和轴突再生密切相关.     

CNTF induces dose-dependent alterations in retinal morphology in normal and rcd-1 canine retina

Ciliary neurotrophic factor (CNTF) provides morphologic preservation of rods in several animal models of retinitis pigmentosa (RP). However, CNTF may alter photoreceptor morphology and rod photoreceptor differentiation in vitro, as well as affecting normal retinal electrophysiology. In addition, the capacity of CNTF to support other cell types affected secondarily in RP (cones and ganglion cells) is unclear. The purposes of this study were to examine the effects of CNTF upon a canine model of RP, the rod-cone degeneration (rcd-1) dog. Archival tissue from a previous study assessing the capacity of CNTF to rescue photoreceptors in rcd-1 dogs was used. One eye was treated for 7 weeks before being explanted. The contralateral eye was untreated. A total of 23 rcd-1 dogs and seven control dogs (four untreated and three CNTF-treated) were used. Morphometric data describing outer and inner nuclear layer thickness, inner retinal thickness, cones and ganglion cells were collected at nine evenly spaced points along each retina and analysed using a mixed effects model. Immunohistochemistry was performed on a subset of 11 dogs for expression of rhodopsin, human cone arrestin (hCAR) and recoverin. CNTF protected the outer nuclear layer and increased inner retinal thickness in a dose-dependent manner (both were maximal at CNTF doses of 1-6 ng day-1). Significant cone loss or reduction of inner nuclear layer width in rcd-1 did not occur in this model, therefore we were unable to assess the protective effect of CNTF upon these parameters. CNTF did not afford significant ganglion cell protection. CNTF induced morphologic changes in rods and ganglion cells, as well as reducing expression of hCAR and rhodopsin, but not recoverin. The dose of CNTF which provided optimal outer nuclear layer protection also resulted in several other effects, including altered ganglion cell morphology, increased thickness of the entire retina, and reduced expression of some phototransduction proteins. These changes were more marked in rcd-1 retinas than in wild-type retinas. This implies that the consequences of CNTF treatment may be substantially influenced by the cellular context into which it is introduced.     

腺病毒介导CNTF基因眼内转移对视神经损伤大鼠F-VEP的影响

目的观察腺病毒(adenovirus,Ad)介导的睫状神经营养因子(ciliaryn eurotrophic factor,CNTF)对视神经钳夹伤大鼠闪光视觉诱发电位(flash visual evoked potential,F-VEP)的影响。方法采用钳夹视神经法制作大鼠视神经损伤模型,夹伤后分别向各组大鼠伤眼内单次注射Ad-CNTF、PBS、Ad-LacZ、CNTF,分别于伤前和伤后1d、14d、28d检测F-VEP的P1波振幅和峰潜时变化。结果伤后1d,各组P1波振幅大幅下降,峰潜时明显延长。伤后14d,各组P1波峰潜时恢复正常,并维持至28d;Ad-CNTF组P1波振幅(10.79μV±2.38μV)与伤后1d(2.97μV±1.21μV)相比,有部分恢复,且好于各对照组。伤后28d,Ad-CNTF组P1波振幅(14.26μV±2.55μV)比各对照组恢复好,差异非常显著(P<0.01);并且好于本组14d时,差异非常显著(P<0.01)。结论视神经损伤后伤眼内单次注射Ad-CNTF可促进受损视神经传导功能的恢复,并可持续到伤后28d。     

Intravitreal injection of ciliary neurotrophic factor (CNTF) causes peripheral remodeling and does not prevent photoreceptor loss in canine RPGR mutant retina

Ciliary neurotrophic factor (CNTF) rescues photoreceptors in several animal models of retinal degeneration and is currently being evaluated as a potential treatment for retinitis pigmentosa in humans. This study was conducted to test whether CNTF prevents photoreceptor cell loss in XLPRA2, an early onset canine model of X-linked retinitis pigmentosa caused by a frameshift mutation in RPGR exon ORF15. Four different treatment regimens of CNTF were tested in XLPRA2 dogs. Under anesthesia, the animals received at different ages an intravitreal injection of 12 microg of CNTF in the left eye. The right eye served as a control and was injected with a similar volume of phosphate buffered saline (PBS). Ocular examinations were performed regularly during the treatment periods. At termination, the dogs were euthanatized, eyes collected and the retinas were processed for embedding in optimal cutting temperature (OCT) medium. The outer nuclear layer (ONL) thickness was evaluated on H&E sections and values in both CNTF- and PBS-treated eyes were compared. Morphologic alterations in the peripheral retina were characterized by immunohistochemistry using cell-specific markers. Cell proliferation in the retinas was examined on semi-thin plastic sections, and by BrdU pulse-labeling and Ki67 immunohistochemistry on cryosections. All CNTF-treated eyes showed early clinical signs of corneal epitheliopathy, subcapsular cataracts and uveitis. No statistically significant difference in ONL thickness was seen between the CNTF- and PBS-injected eyes. Prominent retinal remodeling that consisted in an abnormal increase in the number of rods, and in misplacement of some rods, cones, bipolar and Müller cells, was observed in the peripheral retina of CNTF-treated eyes. This was only seen when CNTF was in injected before the age at which the canine retina reaches full maturation. In XLPRA2 dogs, intravitreal injections of CNTF failed to prevent photoreceptors from undergoing cell death in the central and mid-peripheral retina. CNTF also caused ocular side-effects and morphologic alterations in the periphery that were consistent with cell dedifferentiation and proliferation. Our findings suggest that some inherited forms of retinal degeneration may not respond to CNTF's neuroprotective effects.     

Expression of brain-derived neurotrophic factor in cholinergic and dopaminergic amacrine cells in the rat retina and the effects of constant light rearing

Brain-derived neurotrophic factor (BDNF) regulates many aspects of neuronal development, including survival, axonal and dendritic growth and synapse formation. Despite recent advances in our understanding of the functional significance of BDNF in retinal development, the retinal cell types expressing BDNF remains poorly defined. The goal of the present study was to determine the localization of BDNF in the mammalian retina, with special focus on the subtypes of amacrine cells, and to characterize, at the cellular level, the effects of constant light exposure during early postnatal period on retinal expression of BDNF. Retinas from 3-week-old rats reared in a normal light cycle or constant light were subjected to double immunofluorescence staining using antibodies to BDNF and retinal cell markers. BDNF immunoreactivity was localized to ganglion cells, cholinergic amacrine cells and dopaminergic amacrine cells, but not to AII amacrine cells regardless of rearing conditions. Approximately 75% of BDNF-positive cells in the inner nuclear layer were cholinergic amacrine cells in animals reared in a normal lighting condition. While BDNF immunoreactivity in ganglion cells and cholinergic amacrine cells was significantly increased by constant light rearing, which in dopaminergic amacrine cells was apparently unaltered. The overall structure of the retina and the density of ganglion cells, cholinergic amacrine cells and AII amacrine cells were unaffected by rearing conditions, whereas the density of dopaminergic amacrine cells was significantly increased by constant light rearing. The present results indicate that cholinergic amacrine cells are the primary source of BDNF in the inner nuclear layer of the rat retina and provide the first evidence that cholinergic amacrine cells may be involved in the visual activity-dependent regulation of retinal development through the production of BDNF. The present data also suggest that the production or survival of dopaminergic amacrine cells is regulated by early visual experience.     

高原缺氧对兔视网膜Nogo表达的影响

目的:观察在高原环境下Nogo在北京青紫蓝兔视网膜中的表达和分布。方法:北京青紫蓝兔24只随机分为实验组20只,对照组4只,分别喂养于高原环境和亚高原环境中1,3,7,10,14d取出兔眼球,制成蜡片,应用免疫组化的方法检测视网膜中Nogo的表达及分布。结果:在高原环境下Nogo在兔视网膜中的表达增多,7d达到高峰,持续到10,14d下降,与对照组比较,差异有统计学意义。结论:在高原环境下,Nogo在视网膜急性缺血缺氧损伤可能发挥了重要作用。     

Expression and cellular localization of prolactin and the prolactin receptor in mammalian retina

Prolactin (PRL), originally associated with milk secretion, is known to have a wide variety of biological actions and diverse sites of production beyond the pituitary gland. Recent studies have demonstrated that PRL is synthesized in retinal tissue. To gain insights into the functional role of PRL in the mammalian retina, we mapped the distribution of the PRL protein and the expression and localization of the PRL receptor (PRLR) in the retina of adult rats and green monkeys. PRL was examined in retinal sections by double immunolabeling combining anti-PRL antibodies with antibodies specific for glutamine synthetase (labeling Müller cells), glial fibrillary acidic protein (labeling astrocytes), or neuronal nuclei protein (labeling neurons). PRL was detected throughout the rat retina: in the photoreceptor outer segments, Müller cells, interneurons, ganglion cells, and astrocytes. The PRLR was examined by RT-PCR, in situ hybridization, immunohistochemistry, and Western blot. The long isoform of the PRLR was localized in the photoreceptor nuclear layer, inner nuclear layer, and ganglion cell layer of rat retina. The monkey retina showed a similar distribution of PRL and PRLR immunoreactivities. These findings suggest that PRL functions as a local regulator of various cell types in the mammalian retina.